如何使包含两个父表的内部联接的SQL查询？

Question

I am developing a database containing tables that describes lessons shedule(like at university or in school). I have studied MySQL a little time , so I can't understand fully what I have done) Here is the ERR diagram

Please , have look at group_division table.This table is created to solve that one group can be divited by half and each sub-group won't in the same audiences. So , one teacher will study one sub-group. Now , I have troubles with creating of a query to get

lesson_params.idLesson , lessons_params.time_lesson , 
subjects.Name , audiences.idAudience , teachers.Surname . 

As you can see there are two parent tables - shedule and group_division. So , how to make query to request the data above? It will look like

SELECT lesson_params.idLesson , lessons_params.time_lesson , subjects.Name , 
audiences.idAudience , teachers.Surname FROM

shedule INNER JOIN group_division ON group_division.fk_idShedule = shedule.idShedule
        INNER JOIN subjects ON shedule.fk_subject = subjects.idSubject
        INNER JOIN lesson_params ON shedule.fk_lessons_params = lesson_params.time_lesson
#and,now I need match group_division foreign keys(except fk_idShedule) to its parent tables

I can get the group_division foreign key values

SELECT lesson_params.idLesson , lesson_params.time_lesson , subjects.Name , 
group_division.fk_idTeacher , group_division.fk_idAudience FROM
shedule  
    INNER JOIN group_division ON group_division.fk_idShedule = shedule.idShedule
    INNER JOIN subjects ON shedule.fk_subject = subjects.idSubject
    INNER JOIN lesson_params ON shedule.fk_lesson_params lesson_params.time_lesson;

result

|idLesson | time_lesson | Name | fk_Teacher | fk_idAudience|

Any suggestions?But , please , only not remake the table structure)

Answer 1

Perhaps I'm missing something, but it looks to me like you can just add two more joins:

INNER JOIN teachers ON teachers.idTeacher = group_division.fk_idTeacher
INNER JOIN audiences ON audiences.idAudience = group_division.fk_idAudience

Maybe you are thinking that each INNER JOIN has to reference a column in shedule because it is the first table in the FROM clause. But that's not the case.